Motor driven chain saws are often used in the building industry for making holes in walls and the like, which are made from timber or other easily worked materials. When it is a question of making holes in hard materials, such as concrete, it has been found that utilizing chain saws with success has not been possible. The reason for this seems to be the very difficult working conditions that are met with, inter alia due to the formation of dust, slurry, etc. which gives heavy wear, blockages and other problems which make great demands on the equipment utilized.
Instead, so-called core drills are often used, i.e. a large number of holes are drilled along the defining line of the opening it is desired to achieve, which is obviously laborious and expensive.
Hand-held so-called diamond saws are also used, these being hydraulically driven and water cooled, which requires separate extensive auxiliary equipment. Such a saw has an annular saw blade with an outer edge provided with cutting elements and which is mounted in a drive means at one side so that the saw blade can be caused to circulate, that is, to rotate about its axis. Work with this type of saw is extremely trying and the possible saw blade diameters and saw depths are heavily limited.